Switch and signaling apparatus for telephone systems



' sweets-Sheet 1. G. LANDERS. Switch and Signaling Apparatus for Telephone Systems. No. 228,586. Patented June 8,1880. 1 919.2.

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G. L. ANDERS. Switch and Signaling Apparatus for Telephone Systems. No. 228,586. Patented June 8,1880.

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- G. L. ANDERS, Switch and Signaling Apparatus for Telephone Systems. No. 228,586. Patented'lune 8,1880.

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-- UNITED STATES GEORGE L. ANDERS, OF B SPECIFICATION forming part of Letters Patent No. 228,586, dated June 8, 1880,

Application filed July 21,1879.

To all whom it may concern Be it known that I, GEORGE L. ANDERS, of Boston, in the county Massachusetts, have invented certain new and useful Improvements in Switches, Signaling Apparatus, and Circuits for District-Telephone Systems, of which the following is a specifieation, reference being bad to the accompanying drawings.

In the present district-telephone system, where a series of stations are connected in a circuit and telephonic communication is established between any two stations in the circuit-say the fifth and the seventh stationsall the stations in the circuit between that one of the communicating stations which is nearest to the central office and the central office (in this case the fifth station) are cut off from communication with each other and with the central office.

This is a defect in the system now in use, for the reason that it is desirable that the central office should be able to hold communication with the stations in the circuit at all times.

The object of the first part of this invention is to avoid this defect; and to this end this part of the invention consists in the use of a switch at each station, constructed and connected as described, so that an earth-connection can be established on either side of the telephonic apparatus, according to the direction in which it is desired to communicate, without breaking the continuity of the circuit, thus enabling the central office to still maintain communication on the circuit for any desired purpose, the signaling apparatus being placed between the earth-connection and the central office.

The second part of the invention consists in the combination, with the telephonic apparatus at each station, of a magneto-induction apparatus operated by the depression of a push-knob for generating the current which operates the annunciator or signaling apparatus at the central office.

In the accompanying drawings I have shown the above-named devices as used with a microphonic transmitter known as the Blake transmitter, and a bell-telephone as a receiver, and as combined and arranged together in a convenient manner in a suitable case;

of Suffolk and State of 1 arranged in any manner PATENT ()FFICE.

OSTON, MASSACHUSETTS.

but any form of transmitting or receiving apparatus may be used, and the devices may be found convenient.

Figure 1 is a front view of this case, showing the telephone hook and switch, the monthpiece of the transmitter, and the bindingscrews for making the electrical connections. Fig. 2 is a longitudinal section through the case on the line a 00-, Fig. 1, and shows the signal-bell, switch, transmitter, induction-coil, and magneto-induction apparatus in section. Figs. 3 and 4 are front views of a portion of the case, and show the switch in different positions. Fig. 5 is a back view of the transmitter and switch. Fig. 6 is a sectional view of the signal-bell. Figs. 7, 8, and 9 are diagrams showing theconnections in different positions of the switch; and Fig. 10 is a diagram showing the manner of establishing communication between two stations; but in order to avoid complexity in this diagram the earth-connection is represented as made opposite to the side on which it is desired to communicate, instead of on the same side, as in the actual switch, as shown in Figs. 7, 8, and 9.

In these several figures the same letters refer to the same parts.

In these drawings the microphonic transmitter and receiving-telephone are shown at- J and J, respectively, and, being well known, need not be more fully described.

J is the case or box inclosing and supportin g the several devices.

The switch consists of two plates of metal, K K, attached to the front of the case and separated from each other by a short space, a lever, L, pivoted to a standard on the case, so as to swing from side to side under the plates K K, and a metallic hook, M, or other support, used for supporting the telephone when it is not in use, which hook or other support is attached to the lever L, so as to move with it, but is electrically insulated therefrom.

The end N of the lever L is a spring, or is connected to a spring, and consequently acts to force the other end of the lever against the under side of the plate K or K, aceordin g as the lever is turned to one side or the other, as shown in Figs. 3, 8, and 9, except when the telephone is suspended to the hook or other support, when the lever L and the hook or 'in contact with either other support is depressed so that the leveris not in contact with either of the plates and the hook is brought between the two plates and in contact with both of them, the upper edges of the plates K K being curved downward toward each other for the purpose of guiding the hook, as shown in Figs. 4 and 7.

I disclaim as myinvention a switch at a station forming a portion of the main line and arranged in such relation to an earth-branch at the station that the switch may be moved to break the main line and connect either fragment thereof with the branch to earth.

0 is a metallic spring-arm, which is attached to one side of the case, and extends above the hook M. This arm is bent into a U form near its extremity, and is at such distance from the upper edges of the plates K K that when the hook rises on the detachment of the telephone from its hook or support it makes contact with the spring 0 and one of the plates K K, according to the side thatit is turned, as shown in Figs. 3, S, and 9. This arm 0 is only required when a microphonic transmitter is used,as its object is to complete the local-battery circuit when the battery is in use and the lever L is of the plates K K.

J is the induction-coil used with the microphonictransmitter, the function of which in this connection is well known, and therefore need not be described.

The magnetc-induction apparatus for sending currents from each station to operate the signalbell or annunciator at the central o'tlice consists of a permanent magnet,D, coils E upon the poles of this magnet, and an arma ture, F, attached to one end of a lever, G, which is operated by a rod attached to the push-button I.

The coils E are connected to the circuit, but when the lever G is in its normal position is short-circuited in any suitable manner. A convenient and effective manner of accomplishing this result is to have the armature insulated from the cores of the coils when the armature is separated from them, one terminal of the coils being connected to the armature and the other to the cores, so that when the armature and the cores are in contact with each other the coils are short-circuited.

On depressing the push-button l the coils E are included in the circuit, and by the separation of the armature from the coils an electric current is induced, which is su'fficient to operate the electro-n'iagnet of the annunciator or signal-bell at the central oflice, which electro-magnet must be so constructed as to operate the annunciator by momentary and hightension currents. The electro-magnets ot' the signal-bells at the difi'crent stations on the circuit are not affected by this induced current, owing to being of low resistance. The signalbell is shown in Figs. 1, 2, 5, and 6.

The bell-hammer is operated by a polarized electro-magnet, M, but does not move except when currents of a certain polarity are trans mitted, which currents may be either positive or negative, thus enabling two bells-to be operated in the same circuit, one being operated by positive and the other by n egative currents and this form of signal-bell will form the sub ject of another application for a patent.

The electrical connections are as follows: The line enters at the plate R of the lightnin g-arrester, and the current passes from said plate to the coils of the signal-bell magnet, thence to the m age eto-i nd uction apparatus, the coils E of which are shortcircuited, except when the armature F is separated from the said coil, and thence to the plate K. hen the telephone is on the hook M and the said hook and lever L are depressed by the weight of the telephone, so that the plates K K are connected metallically by the hook, the current will be through the hook M and plate K to the plate R of the lightiling-arrester, and thence to the line and the distant station, and the telephone will be short-circuited; but when the telephone is removed from the hook and the latter rises from contact with the plates K K, and the lever L is swung to make contact with either of the plates K K, according to the direction in which it is desired to communicate, one terminal of the telephonic apparatus will be connected to the line on one side or the other of the switch, and the other terminal will be connected to earth, so that the station will be enabled to communicate by telephone with any station on the side which is connected to the telephonic apparatus.

The signal-bell will always be maintained in connection with the central office, this being the especial object of this invention.

In Figs. 3 and S the lever L is shown as upon the left-hand side, and the circuit is shown as from the central office to the plate R of the lightningarrester, thence to the signal-bell c, thence to the nuigneto-imluction signaling apparatus, thence to the plate K, and through the telephone and the secondary coils of the induction-coil to the plate K, and from thence, by the lever L, to earth, while the local circuit of the transmitter is completed through the arm 0, hook M, plate K, and the primary coil of the induction-coil.

In Fig. 9 the lever L is shown as moved to the right hand, and the circuit from the central oflice passes through the magnetof the signal-bell to earth through the lever L without passing through the telephone; but the circuit from the plate R ot' the lightning-arrester is to the plate K, the secondary coils ol. the induction-coil, the telephone, the plate K, and lever L to earth, and the local circuit is com pleted through the transmitter, the primary coils of the induction-coil, the arm 0, hook M, and plate K.

The operation is as follows: When it is desired to communicate with the central office from any station, the push-knob I is depressed, thereby separating the armature F from the coils E and causing a current to be induced,

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which, though not of sufficient power to operate the electro-magnetic signal-bells at the different stations, owing to the low resistance of their magnets, is able to operate the signalbell or annunciator magnets at the central office, owing to their comparatively high resistance. The telephone at the station communicating is then removed from its hook and the lever L swung to the plate K, whereby the receiving and transmitting instruments are connected on one side to the earth and on the other side to the line and the central office.

Should it then be desired to talk outward from.

a station-say from station No. et-to another stationsay No. 6-the central office is first called by No. 4, and the station made known with which it is desired to communicate. The telephone is then replaced upon its hook, thus cutting it out and establishing a circuit from the central office through the signaling apparatus at stations at and 5 to the signaling apparatus at station 6.. The central office then calls station 6 and gives notice that station 4 desires to communicate, when, by swinging the levers at stations 4 and 6, so as to establish an earth'connection at each of these stations and to place the telephonic apparatus at these stations between the two earth-connections, a circuit is established on which conversation can be carried on, while at the same time, for the reason that station 4 has its earthconnection between the telephonic apparatus and the signal-bell, the central office can call this station and any other station between said station 4 and the central office.

I do not here claim the combination of the plates K K, hook M, and arm L, as this is claimed in my application of March 31, 187 9.

Having thus described my improvements, what I claim as my invention, and desire to secure by Letters Patent, is-- 1. In a district-telephone system, a series of switches, each of which normally short-circuits the telephonic apparatus, and is adapted to establish an earth-connection at each station on either side, according to the direction of the communication, without breaking the continuity of the line, substantially as and for the purpose set forth.

2. In a district-telephone system, the combination, at a station, of a support for a telephone, which support acts by the weight of the telephone, when the latter is in place, to cause the main-line circuit to be established through the said station to the next station, and a device whereby, when the telephone is removed from the support, a connection will be automatically established with earth on either side of the telephone, as may be desired, without breaking the continuity of the line, substantially as and for the purpose set forth.

3. In a district-telephone system, the combination, at a station, of the plates K K, or their equivalents, connected to opposite sides of the line, the hook or support M, acting by the weight of the telephone, when the latter is in place, to electrically connect the plates K K, the spring-lever L, connected to the hook or support M, capable of movement to one side or the other, and when the telephone is removed from the hook maintained in contact with either plate, according to the side to which the lever is moved, an electrical connection from said lever to earth, an electromagnetic call-bell, connected on one side to the plate K, or its equivalent, and on the other side to the central office, and a telephone electrically connected on one side to the plate K, or its equivalent, and on the other side to the plate K, or its equivalent, substantially as and for the purpose set forth.

4.. In a telephone system, a series of individual signaling-bells in an open circuit, each placed at a station and capable of being operated from the central office only, in combination with the magnetic induction apparatus at each station for the purpose of calling the central office, substantially as and for the pur pose set forth.

5. A telephonic circuit having at each station apparatus for receiving signals, apparatus for sending signals, and telephonic apparatus, all included in the main circuit, or in shunts of said circuit, in combination with a switch acting by the weight of the telephone to short-circuit the latter when the telephone is not in use, and when the telephonic communication is desired capable of removing the short circuit and connecting earth to one side or other of the telephone, according to the direction in which it may be desired to communicate, without breaking the main circuit,

'whereby communication may be maintained between stations in the same circuit not ineluded between the stations so connected, substantially as and for the purpose set forth.

6. The combination, substantially as and for the purpose set forth, of the plates K K, hook M, or its equivalent, arm 0, microphone-transmitter, and local circuit.

In witness whereof I have hereunto set my hand on this 2d day of July, 1879.

GEORGE L. ANDERS.

Witnesses:

ALEX. L. HAYES, O. E. ORAM.

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